1128 and 1130 will be on my gravestone

[jdraupp]

My car was built in may of 2002. Not sure where that puts me, but I'm guessing DME 7.8?

Not having a durametric I can only go on what my indy said about my O2 sensors at the time and that was that the two pre cat sensors were not reading the same and the one he replaced showed high resistance. He recommended replacing the pair, however I opted to replace only the one that needed it the most as he was using Porsche o2 sensors and at 350 a pop, I figured I'd rather do the one and swap a bosch sensor in later at 88 bucks for the one that was not replaced.

My fuel trims are about normal. At idle, I'm seeing values between -3.0% and 3.0%. I don't have any fancier values than those, but I'm guessing they should be around that. However I should mention that at startup I initially got some sensor readings at 17 or 18% which I believe indicates lean? Is this normal on a cold start? When the car warms up and regulates idle the trims return to near zero?

I should also add this code does not show up until approximately 400 miles later. Both times this happened it was a long long drive and many starts before the code appeared. Removing oil cap on warm engine causes idle to change and car to bounce a bit, so can I assume that my vacuum system is in order?

[Jager]

Have you tried pouring some Techron into the tank and driving it like you stole it for a couple of hours?

[jdraupp]

That sounds like fun. I may just try that.

[JFP in PA]

Originally Posted by jdraupp

My car was built in may of 2002. Not sure where that puts me, but I'm guessing DME 7.8?

My fuel trims are about normal. At idle, I'm seeing values between -3.0% and 3.0%. I don't have any fancier values than those, but I'm guessing they should be around that. However I should mention that at startup I initially got some sensor readings at 17 or 18% which I believe indicates lean? Is this normal on a cold start? When the car warms up and regulates idle the trims return to near zero?

I should also add this code does not show up until approximately 400 miles later. Both times this happened it was a long long drive and many starts before the code appeared. Removing oil cap on warm engine causes idle to change and car to bounce a bit, so can I assume that my vacuum system is in order?

I don't know how you are determining your idle adaption fuel trims, but here is a good example of an early Boxster recently discussed here:



It is not unusual for a code, particularly an emissions code, to show up only after some miles. The code is actually resident as "pending" until the DME is sure it is for real.

[jdraupp]

JFP, that's the number I got from the fuel trim sensor (short term) using Torque Pro with the blue tooth ELM 327. Is there something else I should be looking for?

[Smallblock454]

@ jdraup:

Hard to say if you have a DME 7.8, or a 7.2. but i think will be a 7.8. There are some differences between US market and EU market. And to be honest I'm more into EU specs and have to do a little more research about US specs.

I think your car doesn't have is a seperate fuel filter that can be changed seperately. This is an integrated part of the the fuel pump since Mj 2002.

I'm with you when it it comes to original Porsche spare part prices. In general they are you relabeled and have the same quality specs. So i would go with Bosch or other quality replacement parts instead of original Porsche parts like Bosch, BERU etc.

If you remove the oil cap and the engine idle bounces a little bit and is rough - that's normal, because the vacuum system has a so to say leak while the oil cap is removed.

Maybe it's best to observe the error codes for some miles and clear it when it comes again. If it shows up too often i would change the 2nd o2 sensor. Because it's an error at idle revs i don't think that will harm anything enginewise. So it's more or less an emission problem. Nothing that really can harm the engine. Nothing that should be written on your gravestone, or from what you should get any grey hairs.

General sensor values seems to be OK to me. Mine's are little different - have a EU car and a S version.

@JFP in PA:
Absolutely with you only to change parts that are broken. But in the case of o2 sensors it's really better to change pairwise, because the DME can generate errors even if the old o2 sensor is working within given specs.

Regards